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<h1><a name="SECTION006600000000000000000">
4.6 <tt class="module">cStringIO</tt> --
         Faster version of <tt class="module">StringIO</tt></a>
</h1>

<p>
<a name="module-cStringIO"></a>

<p>
The module <tt class="module">cStringIO</tt> provides an interface similar to that of
the <tt class="module"><a href="module-StringIO.html">StringIO</a></tt> module.  Heavy use of <tt class="class">StringIO.StringIO</tt>
objects can be made more efficient by using the function
<tt class="function">StringIO()</tt> from this module instead.

<p>
Since this module provides a factory function which returns objects of
built-in types, there's no way to build your own version using
subclassing.  Use the original <tt class="module"><a href="module-StringIO.html">StringIO</a></tt> module in that case.

<p>
Unlike the memory files implemented by the <tt class="module"><a href="module-StringIO.html">StringIO</a></tt>
module, those provided by this module are not able to accept Unicode
strings that cannot be encoded as plain ASCII strings.

<p>
Another difference from the <tt class="module"><a href="module-StringIO.html">StringIO</a></tt> module is that calling
<tt class="function">StringIO()</tt> with a string parameter creates a read-only object.
Unlike an object created without a string parameter, it does not have
write methods.  These objects are not generally visible.  They turn up in
tracebacks as <tt class="class">StringI</tt> and <tt class="class">StringO</tt>.

<p>
The following data objects are provided as well:

<p>
<dl><dt><b><tt id='l2h-486' xml:id='l2h-486'>InputType</tt></b></dt>
<dd>
  The type object of the objects created by calling
  <tt class="function">StringIO</tt> with a string parameter.
</dd></dl>

<p>
<dl><dt><b><tt id='l2h-487' xml:id='l2h-487'>OutputType</tt></b></dt>
<dd>
  The type object of the objects returned by calling
  <tt class="function">StringIO</tt> with no parameters.
</dd></dl>

<p>
There is a C API to the module as well; refer to the module source for 
more information.

<p>
Example usage:

<p>
<div class="verbatim"><pre>
import cStringIO

output = cStringIO.StringIO()
output.write('First line.\n')
print &gt;&gt;output, 'Second line.'

# Retrieve file contents -- this will be
# 'First line.\nSecond line.\n'
contents = output.getvalue()

# Close object and discard memory buffer -- 
# .getvalue() will now raise an exception.
output.close()
</pre></div>

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